Abstract : Phase 2-Tasks 3 and 4 - Non-linear (elastic-plastic) thermostructural analyses were performed for seven PG/SiC codeposited inserts subjected to actual solid rocket test environments. A failure criteria for multiaxial stress fields and orthotropic material strengths was identified and used to predict failure of success of the inserts. A comparison of analytical predictions and actual test results in good correlation. Hence, a baseline was established from which a rational approach to designing codeposited inserts can be developed in the future. (Author)